Linux中的套接字

Question

編譯時出現錯誤：

raja@raja-desktop:~/socket$ g++ Socket.cpp
Socket.cpp: In member function ‘int Socket::recv(std::string&) const’:
Socket.cpp:135: error: ‘cout’ is not a member of ‘std’

Socket.cpp的來源：

// Implementation of the Socket class.


#include "Socket.h"
#include "string.h"
#include <string.h>
#include <errno.h>
#include <fcntl.h>



Socket::Socket() :
  m_sock ( -1 )
{

  memset ( &m_addr,
    0,
    sizeof ( m_addr ) );

}

Socket::~Socket()
{
  if ( is_valid() )
    ::close ( m_sock );
}

bool Socket::create()
{
  m_sock = socket ( AF_INET,
      SOCK_STREAM,
      0 );

  if ( ! is_valid() )
    return false;


  // TIME_WAIT - argh
  int on = 1;
  if ( setsockopt ( m_sock, SOL_SOCKET, SO_REUSEADDR, ( const char* ) &on, sizeof ( on ) ) == -1 )
    return false;


  return true;

}



bool Socket::bind ( const int port )
{

  if ( ! is_valid() )
    {
      return false;
    }



  m_addr.sin_family = AF_INET;
  m_addr.sin_addr.s_addr = INADDR_ANY;
  m_addr.sin_port = htons ( port );

  int bind_return = ::bind ( m_sock,
        ( struct sockaddr * ) &m_addr,
        sizeof ( m_addr ) );


  if ( bind_return == -1 )
    {
      return false;
    }

  return true;
}


bool Socket::listen() const
{
  if ( ! is_valid() )
    {
      return false;
    }

  int listen_return = ::listen ( m_sock, MAXCONNECTIONS );


  if ( listen_return == -1 )
    {
      return false;
    }

  return true;
}


bool Socket::accept ( Socket& new_socket ) const
{
  int addr_length = sizeof ( m_addr );
  new_socket.m_sock = ::accept ( m_sock, ( sockaddr * ) &m_addr, ( socklen_t * ) &addr_length );

  if ( new_socket.m_sock <= 0 )
    return false;
  else
    return true;
}


bool Socket::send ( const std::string s ) const
{
  int status = ::send ( m_sock, s.c_str(), s.size(), MSG_NOSIGNAL );
  if ( status == -1 )
    {
      return false;
    }
  else
    {
      return true;
    }
}


int Socket::recv ( std::string& s ) const
{
  char buf [ MAXRECV + 1 ];

  s = "";

  memset ( buf, 0, MAXRECV + 1 );

  int status = ::recv ( m_sock, buf, MAXRECV, 0 );

  if ( status == -1 )
    {
      std::cout << "status == -1   errno == " << errno << "  in Socket::recv\n";
      return 0;
    }
  else if ( status == 0 )
    {
      return 0;
    }
  else
    {
      s = buf;
      return status;
    }
}



bool Socket::connect ( const std::string host, const int port )
{
  if ( ! is_valid() ) return false;

  m_addr.sin_family = AF_INET;
  m_addr.sin_port = htons ( port );

  int status = inet_pton ( AF_INET, host.c_str(), &m_addr.sin_addr );

  if ( errno == EAFNOSUPPORT ) return false;

  status = ::connect ( m_sock, ( sockaddr * ) &m_addr, sizeof ( m_addr ) );

  if ( status == 0 )
    return true;
  else
    return false;
}

void Socket::set_non_blocking ( const bool b )
{

  int opts;

  opts = fcntl ( m_sock,
   F_GETFL );

  if ( opts < 0 )
    {
      return;
    }

  if ( b )
    opts = ( opts | O_NONBLOCK );
  else
    opts = ( opts & ~O_NONBLOCK );

  fcntl ( m_sock,
   F_SETFL,opts );

}

和Socket.h：

// Definition of the Socket class



#ifndef Socket_class

#define Socket_class





#include <sys/types.h>

#include <sys/socket.h>

#include <netinet/in.h>

#include <netdb.h>

#include <unistd.h>

#include <string>

#include <arpa/inet.h>





const int MAXHOSTNAME = 200;

const int MAXCONNECTIONS = 5;

const int MAXRECV = 500;



class Socket

{

 public:

  Socket();

  virtual ~Socket();



  // Server initialization

  bool create();

  bool bind ( const int port );

  bool listen() const;

  bool accept ( Socket& ) const;



  // Client initialization

  bool connect ( const std::string host, const int port );



  // Data Transimission

  bool send ( const std::string ) const;

  int recv ( std::string& ) const;





  void set_non_blocking ( const bool );



  bool is_valid() const { return m_sock != -1; }



 private:



  int m_sock;

  sockaddr_in m_addr;





};





#endif

Answer 1

將其添加到文件頂部：

#include <iostream>

Answer 2

要添加到約翰的答案中，還請固定以下內容：

// string.h is deprecated
#include <string>
// or
#include <cstring>